In the pneumatic tire, a circumferential groove and a transverse groove are arranged in a tread to obtain wet performance (see Patent Documents 1 to 3).
Conventionally, in the pneumatic tire, various devices are made to improve tire performance (for example, see Patent Documents 4 to 7). In order to improve the drainage on a wet road surface, a groove volume is increased by increasing a groove width or a groove depth.
In a racing ultra-high performance vehicle tire, a technique of linearly arranging several circumferential grooves in a center region of the tread is taken to improve hydroplaning performance, and the technique increases a negative ratio.
Patent Document 1: Japanese Patent Laid-Open No. 57-194106 (FIG. 2)
Patent Document 2: Japanese Patent Laid-Open No. 3-10911 (FIGS. 1 and 2)
Patent Document 3: Japanese Patent Laid-Open No. 11-189011 (FIG. 1)
Patent Document 4: Japanese Patent Laid-Open No. 2001-225611
Patent Document 5: Japanese Patent Laid-Open No. 10-100615
Patent Document 6: Japanese Patent Laid-Open No. 2003-320814
Patent Document 7: Japanese Patent Laid-Open No. 63-061606